Combustion type air heater for house trailers



Dec. 25, 1951 D. a. HOHNSTEIN COMBUSTION TYPE AIR HEATER FOR HOUSE TRAILERS Filed Jan. 17, 1947 w INVENTOR. DEWARD B. Houu STE\ Y E N M T T A Q Patented Dec. 25, 1951 UNITED STATES PATENT OFFICE COMBUSTION TYPE AIR HEATER FOR HOUSE TRAILERS Deward B. Hohnstein, Denver, 0010.

Application January 17, 1947, Serial No. 722,496

4 Claims. 1.

This invention relates to improvements in gas heaters and has reference more particularly to heaters designed with special reference to the heating of automobile trailers of the house type, but which can, of course, be employed wherever a small heating device is desired.

In the heating of trailers, it is quite important that the size of the heating apparatus shall be small as practicable and at the same time it must be so constructed that it operates at a high efficiency.

It is the object of this invention to produce a heater of a comparatively small size that can be operated by means of liquid fuel or bottled gas.

It is an object of this invention to produce a heater of such construction that the heated gas and gases of combustion that pass from the combustion chamber will travel through a heat radiating or transfer chamber in opposite direc tions through tubes provided for that purpose, the tubes being arranged in staggered relation and so positioned that the air that passes through the chamber will all be affected equally by the heated tubes so as to emerge from the heater in a stream uniformly heated.

A further object of the invention is to produce a heater of a simple construction that can be readily made from sheet metal without the use of expensive tools and equipment.

The above and other objects that may become apparent as this description proceeds are attained by means of a construction and an arrangement of parts that will now be described in detail and for this purpose reference will be had to the accompanying drawing in which the invention has been illustrated in its preferred form, and in which:

Figure 1 is a section taken on line l--I, Figure 2;

Figure 2 is a section taken on line 2'2, Figure l; and

Figure 3 is a section taken on lines 3-3, Figures 1 and 2.

Referring now to the drawing, reference numeral l designates the bottom of the combustion chamber H, and reference numeral i2 designates the top of the combustion chamber, which is also provided with sides l3 and I4 and ends 5. The combustion chamber is provided with suitable openings through which access may be had to the burner l6 that has been shown by broken lines in Figure 2. The door or opening into the combustion chamber has been shown in Figure 1 and designated by reference numeral i1.

There is no particular novelty in the combustion chamber or the burner, the latter beingof any approved design for burning gas, if gas is the fuel or for burning liquid fuel, if such is used.

The top of the combustion chamber forms the bottom of a heat radiating and transfer chamber whose end walls have been designated by reference numeral l8, and whose top has been designated by reference numeral IS. A combustion gas receiving manifold 20 is positioned above the top plate 19 and the top of this chamber is formed by plate 2|. Reference numeral 22 designates the fine for the combustion gas.

Positioned within the heat radiating chamber is a radiator assembly comprising two pairs of vertically extending flues. Each pair consists of two flues of identical construction that have been designated by reference numeral 23. Each pair of flues is formed from a plate 24 that is preferably straight and a single plate bent as shown in Figure 3 from which it will be observed that each flue has inclined side walls 25 connected at 26. The joints between plate 24 and the other plate may be formed by welding, riveting or in any other suitable way. The fiues have been shown as trapezoidal shape, but may be rectangular, or any other desired shape. However, it is preferable to have the inner surface, which is formed by plate 24 in the drawing, straight as shown. One flue of each pair is positioned over an opening 21 in plate l2. The flues that are in communication with the combustion chamber are not in direct communication with the manifold 29 and openings 21 are positioned on diagonally located corners of the heat transfer chamber as shown clearly in Figure 3. Oppositely positioned flues of the two pair are interconnected by means of tubes 28 that must be good heatconductors and for this purpose copper tubes have been found very satisfactory.

A fan of the propeller type whose blades have been indicated in a general way in Figure 3 and designated by reference numeral 30 is positioned in a housing whose inclined wall has been designated by reference numeral 3!. The front of the heater has an opening that has been designated by reference numeral 32 in Figure 3. When the fan is operating it produces a current of air that flows in the direction of arrows 33. It will be observed from Figure 2 that the flues 28 are arranged in staggered relation so that all of the air that passes transversely through the heat transfer chamber comes into close contact with the surface of one or more tubes. In Figure 2 the tubes have been shown to what is believed to be a preferable size, but they may be larger in proportion than shown in that figure.

Referring now more particularly to Figure 3, it will be observed that the heated gases from the combustion chamber leave the latter through openings 21, they then pass upwardly through the flues that are in communication with these openings'and pass through flues 28 to the corresponding vertical flue at the other end and finally leave as indicated by arrows 3 1 in Figure 1. With the construction shown it is evident that all of the heated gases thatleav' the-com bustion chamber through the opening 21 at the lower righthand corner in Figure 3 pass through the tubular flues 29 in a direction towards the left, while the heated gases that enter through the opening 21 at the upper lefthancl. corner.

flow in the opposite direction. When the fan is operating and the air flows in the direction of arr ow;33, the airgwill naturally absorb heat from group will, strike the next set of flues at the end where they are thehottestand as a result of this all of the air that passes throughthe heating chamber will have the same opportunity to absorb, vheat by conductiOn and radiation and the stream that enters the trailer or other room inwhich the heater is positioned will be uniformly heated at all points or its transverse area... If, for example, all of the heated gases flowed, in'thesa-me direction-through flues 28, the gases that contact only the cooler ends of thesefiues would emerge at a much lower temperature than the gasesthat contact the hotter ends. With the construction shown, a uniform heating of theair results which gives a higher efiiciency of heat transfer and since the air from the heater isof the same temperature, it obviates the objectionable feature presentin heaters of this type, in which the air is heated to difierent temperatures in layers. perpendicular to the direction of recreating flues, is absent.

The size of, the heater is, of ccli'i'rs'e,v immaterial so far as its patentable features are concerned. repay bes tated, however, that the overall height is approximately twelve inches;

its maximum width is. the same, while thedi'stance from .front to back is approiiir'nately six inches, making a small compact heater for which space can readily be found in any trailer. Having described the invention what is claimed as new is: e

1. A heaterfor a'gas such as air, comprising, means for effecting a flow of. gas-in a given direction, a group of substantially araner flue gas tubes disposed laterally of the direction of flow of said gas, means for supplying the interior of said tubes with flue gas at substantially uniform temperature and for flow therethrough in one direction, a similar group of tubes disposed downstream of the gas flow, means for supplying said similar group of tubes with flue gas at substantially uniform temperature and for flow therethrough in a direction opposite to said first group, meansto supply'both groups of tubes with flue gas from a commonhsource; and .rneans for collecting and discharging flue gas from all said tubes.

2. A device as set forth in claim 1 wherein the "tubesfofthe' groups are staggered.

of horizontal flues connecting the interior of the opposed flues, a second similarpair of vertical flues arranged in opposed spaced relation and spaced from the first pair, a similar, group of horizontal flues connecting the interior of the second pair of opposed flues, the fiufes being disposed substantially along the'c'olrnrsi of a rectangular parallelepiped, two of the flues, disposed along diagonally opposite corners of the parallelepiped, having their lower ends 7 lofnmunication with thecombustion chamber and their upper ends closed, the other twobf the flues, disposed along the other diagonally opposite corners of the parallelepiped, having their lower ends closed and their upper ends in communication with the manifold. the arrangement being such that heated gases from the combustion chamberwill enter one'flueofeach opposed pair, pass through horizontalflues to its opposed flue and'then into the manifold, whereby the hot gases will flow in oppo'site directions through the tWo groups of'ho'rizontal flues, and means forproducing a flow of air transversely of the horizontal fl'u'es.

4. A heater in accordance with claim 3 herein the tubes of the groups are staggered.

*DEWARD B. HOI-INSTEIN.

REFERENCES CITED The following'references are of record in the file of this patent: I V v UNITED STATES PATENTS Number Name Date 355,301 Condit Jan. 4, 1887 752,002 Sh'afer Feb. 9, 1904 1,713,984 Schramm July 2, 1929 1,745,239 Bahnson i 'l Jan. 28;1930 1,754,952 Humphrey Apr. 15, 1930 1,769,994 Hendryx July 8, 1930 1,834,579 DOWd Dec. 1, I931 

